NARROW AISLE RACKING (VNA)

Aisle Width, Guidance and Truck Pairing

The aisle dimension is dictated by the truck, so we specify the two together or not at all. A typical articulated VNA truck handling a 1200 x 1000 mm pallet crossways needs 1,650–1,800 mm clear between pallet faces; man-up turret trucks lifting to 12 m usually want 1,800–1,900 mm. We add floor-fixed guide rails at 100 x 50 mm channel, or wire guidance cast into the slab where you want a clean floor for cleaning machines.

Height is where VNA earns its money. Lifting to 12–14 m instead of 7 m doubles positions again, but only if the slab can take it. VNA aisles are subject to FEM 4.001 floor flatness — far tighter than a normal warehouse slab — and we survey levels along every proposed aisle before design. Where the slab misses tolerance we either grind, or drop the design height and tell you honestly what it costs you in positions.

Frames are usually specified one gauge heavier than standard APR because of the lift heights involved, with 1,100 mm deep frames for a 1,000 mm pallet, run-spacers between back-to-back runs, and top ties across every aisle for stability.

• Aisle widths from 1,600 mm to 1,900 mm clear
• Lift heights commonly 9,000–14,000 mm
• Wire guidance or mechanical rail guidance to suit your truck fleet
• 100% pallet selectivity retained — no honeycombing losses
• Frames, run-spacers and top ties designed to FEM 10.2.02
• Floor flatness surveyed to FEM 4.001 before design sign-off

The Real Cost Case for Going Narrow Aisle

VNA is not the cheapest racking per position — the trucks, the guidance and the slab work see to that. It is almost always the cheapest storage per pallet when you compare it with the alternative most operators are facing: renting a second building. A 3,000 m² unit at Midlands rents costs more each year than a full VNA conversion costs once.

The trade-off is truck flexibility. A guided VNA truck lives in its aisles; you will still need a counterbalance for loading bays and a reach truck for bulk areas. We routinely design mixed layouts — VNA in the main store, two wide-aisle runs at goods-in for cross-docking — because a warehouse that only works one way is a warehouse that struggles at Christmas.

Lighting, sprinklers and racking must be planned together at these heights. In-rack sprinklers are commonly required above 9 m depending on the commodity classification, and aisle lighting should be re-hung to run down the aisle centre rather than in a standard grid, or your pickers will be working in shadow at the top beam level.

Safety, Damage Control and Inspection at Height

Damage in a narrow aisle is more consequential than anywhere else in the building because clearances are tight and heights are extreme. We fit end-of-aisle protection, full-height frame protectors on the first bays and floor-fixed guide rails that take the truck's rub loads instead of your uprights. Where guided trucks are already in use, worn guide rollers are the most common cause of upright damage we see on inspection.

HSG76 and SEMA guidance apply as they do anywhere else, but at 13 m a red-risk upright is a very different conversation. Our SEMA-approved inspectors work the aisles with access equipment, photograph and grade every defect, and issue a prioritised report with drawings showing exactly which frame in which run needs attention. Repairs use manufacturer-matched or SEMA-compliant repair components — never welded plates, which invalidate the rack design.